Do you by any chance have any references where they show that OS is more susceptible to jitter than NOS? I can understand it would be in the presence of noise-shaping, but at present I can't see how OS without NS is any worse-off in respect of jitter.

Well, no, but if you add a specific phase error to a clock signal then the relative error will be greater the higher the frequency.
For instance, if you have a 10 second square wave, a 100 mS error is 1%, but would be 10% if the square wave had a period of 1 second.

Because a NOS DAC is essentially a lower frequency circuit, it is easier to build successfully (not just for this reason). 4x and 8x OS is approaching what is reasonable to build what with signals running at about 2-4 MHz. Any more than that, and you're forced to consider PCBs with groundplanes and working with SMD - not a good choice for a first DAC.
Class D amplifiers are another example of stuff that's hard to do as basic DIY. I think NOS isn't. It's relatively simple to do, which is one reason why it is popular.

It's harder to do, but I think OS will offer better results, because the correct analogue filtering can be implemented easily - compared to the correct filtering for NOS.

"No, I don't think I've it all. You are making an assertion about how mass market audio has improved without providing any facts or analysis to support that."

Ken from Pen, are you serious ? I need to prove that a 2011 mid priced mass market Denon system will sound better than my Dads old 60's stereogram .... I think my ears on this occasion will suffice.

"What do engineers being pressured to cut costs have to do with the use of extreme amounts of negative feedback to greatly improve an amplifier's THD specification, for example? "

Ken, see above, the mass market audio buyers just dont care enough. What would be the point of tweaking a low cost amp or cd player and yes making an improvement only for it to be lost by the low quality speaker cable, speakers and cabinets supplied in a mass market system. And then to be followed by a non hi fi enthusast who will place his speakers where they look best, not sound best.
So, for example, he or she will probably put the main system in front of that noisy filter by the fish tank, left speaker on the drinks cabinet and right speaker on the window sill....... whats the point ?

How about we compare that 2011 Denon system with an old Hafler Stereo 70, or even a vacuum tubes amp from the 60's and 70's, all mass market in it's day. Or, how about a 70's vintage Technics belt drive turntable to and equivalently priced CD-player of today. No, my friend, the question is, are YOU serious. Perhaps, you are simply lacking the necessary historical perspective to make the argument which you have been attempting, I can't tell.

As far the the listening values of mass marker consumers are concerned, if they cared nothing about the sound they would only by small table radios and portable CD players, not the more costly DENON type component systems which many of them do purchase, yes? So, sound quality clearly is a value held by the mass market audio consumer, as are convenience and style. The fact that such consumers may have never learned or been taught how to properly set-up their component systems to deliver the most listening pleasure does not constitute proof that they don't values the sound quality.

This is likely my last comment about this subject with you, as the discussion has become more argumentative than mutually informative.

Let me comment about the OS-NOS debate. No manufacturer will be able to bring a "technically imperfect" mass product on market. The competition and technically half-educated consumers/magazine reviewers would discredit them. I mean by "technically imperfect" an OS DAC putting out stepped signals instead of nice smooth signals, not being flat frequency response up to the magic 20 kHz, an amplifier having no NFB and having >1% THD, etc. Most consumers select a mainstream product by specifications first, and the manufacturers are aware of it. Secondly, the development engineer have a technical attitude - their task is to develop technical products based on technical specifications, not musical instruments.